The exemplary embodiments described herein relate to low residue, high salinity fracturing fluids.
Aqueous gel fluids are used to treat subterranean formations penetrated by wellbores in a variety of ways. For example, such fluids may be used to temporarily plug or block a portion of a formation to allow a gravel pack to be placed in the formation. Aqueous gel fluids may also be used to fracture subterranean formations in order to stimulate the production of fluids, such as hydrocarbons, therefrom.
In a fracturing treatment, an aqueous gel fluid may be injected down the wellbore at a pressure sufficient to develop hydraulic forces that create or extend at least one fracture in the formation. The gel quality of the fluid aids in both the suspension of proppant material in the fluid and the formation of the fracture. Elevated pressure is maintained on the fluid for a sufficient time to cause movement of the fluid into the fracture and thereby propagate or extend the fracture into the formation. The proppant material in the fluid may deposit in the fracture so as to hold the fracture open upon release of the pressure. Crosslinking agents may be used to increase the viscosity of the fluid, which facilitates transport and placement of the proppant material and the formation of an extended fracture.
In some instances, it may be desirable to recover the aqueous gel fluid from the formation once the treatment is complete and prior to initiating or resuming hydrocarbon production. In order to recover the fluid, it may be necessary to first reduce the viscosity of the fluid by causing the gelling agents in the fluid to break down, which is commonly referred to as “breaking” the gel.
In some instances, the process of breaking the aqueous gel fluid creates microscopic gel fragments, often referred to as “gel residue.” Gel residue may, in some instances, agglomerate or flocculate and form relatively large broken gel masses. These masses can severely damage the formation. For example, the masses may plug the interstitial spaces of a proppant pack formed in a fracture and may severely reduce the flow of fluids therethrough, which reduces hydrocarbon production from the formation.